Python网络通信

day26

网络通信

参考：

http://www.cnblogs.com/yuanchenqi/articles/5692716.html

男生是client端，字条是socket（sk），通过sk通信。

socket属于客户端。应用程序两端通过“套接字”向网络发出请求或者应答网络请求。可以把socket理解为通信的把手（hand）。

确定对端IP地址→ 确定应用程序端口 → 确定通讯协议

server下的方法

bind()

listen()

accept()

recv()

send()#传送内容必须为bytes类型

sendall()

close()

client下的方法

connect()

recv()

send()

aendall()

close()

client发送，serve接收

serve.py

 import socket

 sk = socket.socket()#创建socket

 print(sk)

 address = ('127.0.0.1', 8000)#本机地址
 sk.bind(address)#为socket绑定IP和端口号

 sk.listen(3)#限制排队的个数
 print('waiting......')
 conn, addr = sk.accept()#conn为客户端socket对象
 #
 # inp = input('>>>')
 # conn.send(bytes(inp, 'utf8'))

 data = conn.recv(1024)#为什么用conn，而不用sk
 print(str(data, 'utf8'))

 # conn.close()#关具体对象
 # sk.close()#全关

client.py

 import socket

 sk = socket.socket()

 print(sk)
 address = ('127.0.0.1', 8000)

 sk.connect(address)

 #data = sk.recv(1024)#收到的为bytes类型
 data = sk.send(bytes('hah', 'utf8'))

 #print(str(data, 'utf8'))

运行serve.py

<socket.socket fd=3, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('0.0.0.0', 0)>
waiting......

waiting，accept()阻塞。

运行client.py

<socket.socket fd=3, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('0.0.0.0', 0)>

Process finished with exit code 0

serve收到数据“hah”

<socket.socket fd=3, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('0.0.0.0', 0)>
waiting......
hah

Process finished with exit code 0

client接收，serve发送

serve.py

 import socket

 sk = socket.socket()#创建socket

 print(sk)

 address = ('127.0.0.1', 8000)#本机地址
 sk.bind(address)#为socket绑定IP和端口号

 sk.listen(3)#限制排队的个数
 print('waiting......')
 conn, addr = sk.accept()#conn为客户端socket对象

 inp = input('>>>')
 conn.send(bytes(inp, 'utf8'))

 # data = conn.recv(1024)#为什么用conn，而不用sk
 # print(str(data, 'utf8'))

 # conn.close()#关具体对象
 # sk.close()#全关

client.py

import socket

sk = socket.socket()

print(sk)
address = ('127.0.0.1', 8000)

sk.connect(address)

data = sk.recv(1024)#收到的为bytes类型
#data = sk.send(bytes('hah', 'utf8'))

print(str(data, 'utf8'))

运行serve.py

<socket.socket fd=3, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('0.0.0.0', 0)>
waiting......

运行client.py

<socket.socket fd=3, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('0.0.0.0', 0)>

在serve命令行输入hello

<socket.socket fd=3, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('0.0.0.0', 0)>
waiting......
>>>hello

Process finished with exit code 0

client命令行收到数据。

<socket.socket fd=3, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('0.0.0.0', 0)>
hello

Process finished with exit code 0

不间断聊天

client.py

 import socket

 sk = socket.socket()

 print(sk)
 address = ('127.0.0.1', 8000)
 sk.connect(address)

 while True:
     inp = input('>>>')
     if inp == 'exit':
         break
     sk.send(bytes(inp, 'utf8'))

     data = sk.recv(1024)
     print(str(data, 'utf8'))

 sk.close()
 #print(sk)

serve.py

 import socket

 sk = socket.socket()#创建socket

 print(sk)

 address = ('127.0.0.1', 8000)#本机地址
 sk.bind(address)#为socket绑定IP和端口号

 sk.listen(3)#限制排队的个数
 print('waiting......')
 #conn, addr = sk.accept()#conn为客户端socket对象

 while True:
     conn, addr = sk.accept()
     print(addr)    #client打开则接收
     while True:
         #收
         try:
             data = conn.recv(1024)#为什么用conn，而不用sk,client关闭时报错误
         except Exception:
             break  #client端停止，他也停止
         print('.......',str(data, 'utf8'))
         if not data:break
         #发
         inp = input('>>>')
         conn.send(bytes(inp, 'utf8'))

 sk.close()#全关

不间断聊天，其中client若关闭，新开一个client，serve端还能继续服务。

粘包现象（远程执行命令）

cmd_client.py

 import socket

 sk = socket.socket()

 print(sk)
 address = ('127.0.0.1', 8001)
 sk.connect(address)

 while True:
     inp = input('>>>')
     if inp == 'exit':
         break
     sk.send(bytes(inp, 'utf8'))
     result_len = int(str(sk.recv(1024), 'utf8'))

     sk.sendall(bytes('ok', 'utf8'))#收到长度信息后，告诉server

     data = bytes()#初始化
     while len(data) != result_len: #等于原文件大小，说明接收完
         recv = sk.recv(1024)
         data += recv

     print(str(data, 'utf8'))

 sk.close()
 #print(sk)

cmd_server.py

 import socket
 import subprocess
 sk = socket.socket()#创建socket

 print(sk)

 address = ('127.0.0.1', 8001)#本机地址
 sk.bind(address)#为socket绑定IP和端口号

 sk.listen(3)#限制排队的个数
 print('waiting......')
 #conn, addr = sk.accept()#conn为客户端socket对象

 while True:
     conn, addr = sk.accept()
     print(addr)    #client打开则接收
     while True:
         #收
         try:
             data = conn.recv(1024)#为什么用conn，而不用sk,client关闭时报错误
         except Exception:
             break  #client端停止，他也停止
         print('.......',str(data, 'utf8'))

         if not data:break
         obj = subprocess.Popen(str(data, 'utf8'), shell = True, stdout = subprocess.PIPE)
         cmd_result = obj.stdout.read()#以上执行结果
         #print(cmd_result)
         result_len = bytes(str(len(cmd_result)), 'utf8')

         conn.sendall(result_len)#发
         #先向client发送数据，client若收到则向server发送OK，Server再发送处理结果
         #若连续发送，两个发送内容（长度，处理结果）可能会合并。
         re = conn.recv(1024)#防止粘包
         if str(re, 'utf8') != 'ok':
             break
         #发
         conn.sendall(cmd_result)

         # conn.sendall(result_len)  # 这种方式会发生粘包现象，长度和内容合在一起了
         # conn.sendall(cmd_result)
 sk.close()#全关

先执行server.py,再执行client.py,在client中输入命令（dir,pwd,ifconfig等）